Multiplex-channel repeater system



. 1 617 993 Feb. 15, 1927. w. A. DUDLEY ET AL 9 MULTIPLEX CHANNEL REPEATER SYSTEM Filed Feb. 10. 1925 attic: 144111 Iatented Feb. N15, 1

UNITED STATES PATENT OFFICE.

\VILLIAM DUDLEY A ND KARL B. DUERR, OF BROOKLYN, NEW YORK, ASSIGNORS TO THE WESTERN UNION TELEGRARH COMPANY, OF NEW YORK, N. Y., A CORPORA- TION OF YORK MULTIPLEX-CHANNEL REPEATER SYSTEM.

Application filed February 10, 1925. Serial No. 8,285.

This invention relates to multiplex telegraph repeater systems and comprises means whereby telegraph messages received at a central station over' a multiplex system may 5 beautomatically repeated to the'branch oflice for which it was intended.

According to present practice the incoming telegraph business offa large city is received at a large central ofiice fro n which it is distributed to various branch ofiices by "means .of Morse Wires, telephone or pneumatic tubes. In each instance this involves 'azlsecond handling of the messages thereby incurring added cost and introducing the possibility of error.

When the volume of business between a main oflice in one city and a branch oflice in another city is sutficient to warrant the expense, a multiplex system is installed.

However, there are many instances Where the volume of business is only suflicient to fill a single channel of the multiplex. In such cases it would be very desirable if the messages transmitted over one of the several "'2 channels joining the main oflices in the two cities could be repeated automatically to the branch ofiice, thus relieving the main'oflice of the work and transferring it to the branch ofiice which is its ultimate destination.

The object-of our invention is to devise a. system for carrying out thefunctions above mentioned by means of apparatus having a low initial cost and requiring a minimum of maintainance expense. This apparatus may be applied to any of the multiplex channels at either or both ends. In the following description, we shall refer to the accompanying drawing in which it will be noted. that two line wires are shown 4 between the main and branch oflices. It is evident, however, that a single duplexed line may be employed though for short distances it is more economical to use two wires, there.- by avoiding the use. of duplex balanclng apparatus.

The drawing illustrates diagrammatically a multiplex system having three channels A. B andC.- The five segments of channel B of the sending distributor SD at station A, are shown connected to the tongues of a transmitter T which may be' of the wellknown type disclosed in Benjamin Patent- No. 1,298,440; The main line ML connecting the line relays .LR at main stations is shown duplexed at either end. The signals transmitted from stationA' over channels A and C are recorded by the usual printers connected to the corresponding segments of the receiving distributer RD at station B in accordance with the well known multiplex practice. The signals sent over theB channel are automatically repeated at station B and transmitted to the branch ofiice where they are recorded by the printer PTR.

At station B, the segments of the B channel of the receiving distributer RD are connected respectively to the five polarized relays PR. one terminal of each relay being connected to the middle point of a potentiometer pt. It is evident that any combination of signals sent out by the transmitter .'I over the B channel will be received on the segments of the B channel of the receiving distributer RD at station B, and will be set up on the polar relays in an exact duplicate of the original transmitter combination. The tongues t of these five relays are connected respectively to five segments of a* start-stop distributer SSD whose solid sending rin is connected to the receiving line RL lea ing to the line relay LR at the branch oflice. 1 7

Now assuming that the proper phase and speed relations exist between the multiplex and'start-stop distributors, it is evident that as the brushes of the start-stop distributer pass over the segments, the combination stored in the bank of polar relays PR, will be retransmitted fromthe line battery LB, to the. branch oflice where they are received on the segments of the receiving distributer RD and transmitted to the selecting magnets of the printer PTR ,and thereby recorded. Y

In order that the t'ongues pf the relays may operate and settle firmly on their'contacts before the signals are repeated, the

start-stop distributer brush is stopped on the rest segment R until the relays have received thesignal impulses of the combination; Thereafter a brush 6 on the multiplex distributer RD closes a circuit-through a segment 8 on a local ring which actuates the startmagnet SM, thus releasing the brush 6 of the start-stop distributer S- SD. ,The speed of this brush must be greater than that of the multiplex brushes so that it will have passed off of the segment connected to a relay before that relay is again operated. The phase relation between the multiplex and the start-stop apparatus is antomatically established since the start-stop distribute-r is controlled by a local se ment on It When they are arrested by the armaturecatch of the stop magnet. When the brush arm is released by the start magnet the brushes mov'e over-the segments inisynchronism with the brushes on the start-stop distributer S.SD and thereby set 11 on the five selector magnets of the printer TR, the combination which was locked up on the armatures of the magnets PR at station B.

As the brushes ass over the last segment on the distributer D a circuit is closed from a local battery to ene ize the printer magnet PM, thereby recor ing the si nal transmitted, from station A over the B channel I of the multiplex between the main stations and automatically repeated from station B to the "branch oflice by means of the start strgi 'distributers. I

essages may also be sent in the reverse direction from the branch office to main station-A, being automatically re eated at main station 'B into the B channe ofthe multiplex between the main stations. rangement ofthe apparatus is diagrammati cally shown in the lower part of thefigure.

'The transmitter T at the branch ofiice isconnected to the sendin segments of a startstop distributer S-S 2 the solid ring of which'is. directly connected to the branch ofiice sendingline SL. The brushes 6 of the distributer rest upon the segments B when the brush arm has been arrested by the armature-hook of the start magnet SM. When the sendin brushes b are released the a combination ofsignal impulses set up on the 50 transmitter T are transmitted over the "branch line. SL andare selected by the line relay LR and the segments of the start-sto distributer S---SD at the'main station and caused to operate a bank of polar relays- PR, in the same manner as previously described for the transmission ,in the opposite direction.

The tongues 25 of these five polarrelays PR are connected to the five sending seg- .ments of the B channel of-th'e multiplex distributer RD, so that as the brushes pass over these segments the combination of si "nal impulses sent from the branch ofiice is sent over the multiplex line'ML and received in the usual manner bythe line relay LR, the

The artongue of which transmits the corresponding at station A on the printer of the B channel. 1

It is evident that some provision must be made fofitiming the motion of the tongues of the relay magnets PR so that each combination of signal impulses will be set up before they are repeated into the multiplex B channel. This is accomplished by controlling the start of the sending brush 1: 1;

at the branch oflice from a local segment on the multiplex ,distributer RD at'main sta tion B in. the same manner as previously described for thetransmission in the opposite direction. It is obvious that it would be impractical to run a third line between main station B and the branch oflice for the sole purpose of furnishing this start impulse. We therefore rovide means for transmitting this start impulse as an increment over the branch office sending line SL. A Morse relay MR at station B, actuated by the pass ing of a brush 6 over a local segment on the multiplex distributer RD, short-circuits a resistance r in the branch oflice sending line, thus momentarilyincreasing-the line current. A. second Morse relay MR? located at the branch oflice is adjusted so that it is nonoperative on the normal line current but responds to this increased value. When the latter relay operates by virtue of the increased increment of line current, it closes a circuit through. the sendin start magnet SM which releases the send' 7 In thismanner the start-stop system for the outgoingzmessages from the branch ofiice is held in ,a definite fixed phase relation with mg brushes b. V

respect to the multiplex system between the Operation of the start-stop system conforms in the main to other standard systems, but in ourpresent system the receiving brush doesnot necessarily run faster than the sendmg brush. This is made possible by the fact that the-sending brushes are stopped, which gives-the receivin brush time to catch u with the'sending rus It will'benoted from t e theoretical circuits shown in the drawing that the receiving start while it is stoppe ing impulse is transmitted over branch line RL. This operates the linerelay LE at the other end of the start-stop system which closes a circuit from battery through its marking contact, the brushes of thereceiving distributer and the start magnet SM which withdraws its armature-hook from the brush-arm and permits the brushes to start. r i

The speeds of the two start-stop distributers S-SD and RD are adjusted as closely as possible to the same value. The sending brush 6 when released transmits a start pulse which releases the receiving brush 1) at the other end. Bothbrushes then make one revolution and stop ready to be started again in the same way. This means that at the beginning of each revolution 'the sending brush and its corresponding receiving brush start in a true phase relation and even though the two speeds be somewhat at variance, they do not get far enough out of synchronism during one revolution to prevent proper operation.

e claim- 1. In a telegraph system, a plurality of stations, a multiplex synchronous system connecting two of said stations, a start-stop system extending from one of said stations to a distant station, said start-stop system embodying {independently actuated rotary distributors designed tooperate at substantially the same speed, means for transmitting codecombinations ofi'mpulses'over said multiplex system, means for automatically repeatingsaid impulses from said multlplex system to said start-stop system, means controlled by the multiplex apparatus for resystem extending from one of said stations to a distant station and embodying rotary distributors actuatedvindependentl of the signal impulses and operating in su stantial synchronism, means for transmitting code combinations of signal impulses over said multiplex system, means for automatically repeating said impulses from said multiplex system to said start-stop system, means controlled by the multiplex apparatus at the repeating station for releasing the start-stop distributor at that station, and means controlled by said last-mentioned distributor for releasing the start-stop distributor at the distant station.

3. In a telegraph system, a plurality of stations, a multiplex synchronous system connecting two of said stations, a start-stop system extending from one of said stations to a' distant station and embodying rotaryv distributors actuated independently of the signal impulses and operating in substantial synchronism, means for transmitting code combinations of signal impulses over said start-stop system, means for automatically repeating said code signal impulses from said start-stop system to said multiplex system, means controlled by the multiplex apparatus at the repeating station for releasing the start-stop distributor atthe distant station, and means controlled by said lastmentioned distributor for releasing the start-stop distributor at the repeating station. a

4. In a telegraph system as set forth in claim 3, said means, for releasing the startstop distributor at the distant station emstations, a multiplex synchronous system' connecting two of said stations, a start-stop system extending from one of said stationsto a distant station, means for transmitting message impulses over said multiplex system, means for transmitting message impulses over said start-stop system, and

'means ior simultaneously transferring message impulses from said multiplex-system to said start-stop-system and from said startstop system to said multiplex system, each of said last two means embodying a set of polar relays for locking up the signal impulses be-' tween the multiplex and the start-stop system, said start-stop system embod n rotary distributors actuated indepen ently of the signal impulses.

In testimony whereof we aflix our signa: tures. k

.WILLIAM A. DUDLEY.

- KARL B; DUERR.

.95 bodying means responsive only to an abnor- 

